Semiconductor device and manufacturing method thereof

ABSTRACT

The semiconductor device comprises a first area and a second area positioned adjacent to the outside of the first area, the semiconductor substrate having a main surface and side surfaces and disposed in such a manner that the main surface is positioned in the first area and each of the side surfaces is positioned at a boundary between the first area and the second area, a plurality of pads formed over the main surface of the semiconductor substrate and a plurality of external connecting terminals formed thereon, which are respectively electrically connected to the pads, a first resin portion which is formed over the main surface of the semiconductor substrate so as to cover the pads and has a main surface and side surfaces, and which is formed in such a manner that the external connecting terminals are exposed from the main surface and each of the side surfaces is positioned at the boundary, and a second resin portion which is positioned in the second area and formed so as to cover the side surfaces of the semiconductor substrate and the side surfaces of the first resin portion and which is different in composition from the first resin portion.

BACKGROUND OF THE INVENTION

The present invention relates to a semiconductor device and amanufacturing method thereof. The present invention relates particularlyto a small-sized semiconductor device corresponding to a wafer levelchip size package (W-CSP) and a manufacturing method thereof.

There has been an increasing demand for miniaturization and thinning ofa semiconductor device with semiconductor elements being packagedtherein. There has been proposed a CSP (Chip Scale Package) whereinspherical terminals are disposed on the surface sides of semiconductorelements in lattice form in the field of a demand for its thinning inparticular. There has also been proposed a wafer level chip size package(W-CSP) built into a CSP in a wafer state.

The W-CSP is one in which individual semiconductor devices formed on awafer are fractionized and divided by a dicing saw or the like. However,cut surfaces are exposed at the side surfaces of the fractionizedsemiconductor devices, and fine cracks and chipping occur.

Therefore, in order to prevent the occurrence of such chipping andcracks, there has been proposed a semiconductor device molded with aresin after grooves or trenches relatively wide in width are formed inareas to be diced (refer to, for example, patent documents 1 (JapaneseUnexamined Patent Publication No. Hei 10(1998)-79362), 2 (JapaneseUnexamined Patent Publication No. 2000-260910) and 3 (JapaneseUnexamined Patent Publication No. 2006-100535)).

Since, however, all of the above-described semiconductor devices on thesemiconductor wafer including the trenches at any thereof are moldedwith the same resin, a resin must be selected which combines bothadhesion to the semiconductor wafer and an electrical insulatingproperty. That is, the resin charged into the trenches must be firmlyadhered to the semiconductor substrate even after dicing. On the otherhand, there is a need to select a resin having insulation enough tosuppress leak current. Thus, the selection of a resin most appropriateto respective spots has been required.

Such a semiconductor device and its manufacturing method will beexplained specifically.

FIG. 5(A) is a sectional view of a semiconductor wafer prior toexecution of mold formation. As shown in FIG. 5(B), trenches 132 arerespectively formed in dicing areas of a semiconductor wafer 131. Thetrenches 132 are formed in all the dicing areas of the surface of thewafer. Next, as shown in FIG. 5(C), the trenches 132 are filled with amold resin 133. As a matter of course, the mold resin layer 133 isformed even within the trenches 132. Thereafter, as shown in FIG. 5(D),the mold resin layer 133 is polished or ground to form a mold resinlayer 134 having a desired thickness. Finally, as shown in FIG. 5(E),full cut portions 135 are respectively formed in the trenches 132 withwidths each narrower than the width of each trench 132. With theformation of the full cut portions 135, the mold resin layers 134 lyingwithin the trenches 132 are also separated from one another and leftbehind as grip portions.

Thus, the conventional semiconductor device involves the above-describedproblem because the compositions of the grip portions and other portionsare comprised of the same resin portion.

The following problems arise in the method for manufacturing thesemiconductor device having the above-described grip structure. In orderto make adaptation to an actual manufacturing process, there was a needto take some measures thereagainst.

Since the trenches 132 are first formed and the mold resin layer 133 isformed in the conventional manufacturing method, cracks of thesemiconductor wafer 131 occur with the trenches 132 as points of origindue to a pressure-applying process or the like necessary to charge themold resin. There was a possibility that since the semiconductor elementareas were exposed before the formation of the mold resin layer 133,chips and particles produced by processing of the trenches 132 would beadhered to the semiconductor element areas, thereby causing a qualityproblem. Further, since a state under the mold resin layer 133 cannot beconfirmed where the mold resin layer 133 is formed, there is a need toprovide steps for performing an inspection and measurements necessarybefore the formation of the mold resin layer 133. Upon this inspection,the confirmation of finished quality of each trench 132 and clean-upprior to mold processing are required again. The risk of wafer breakagewith a conveying process and wafer handling becomes high. In addition,processing environments prior and subsequent to mold resin processingnormally differ and processing under the environment high in cleanlinessis essential before the mold resin processing. On the other hand, dicingprocessing executed after the mold resin processing is not normallyexecuted under the environment high in cleanliness. Therefore, there isa need to perform the respective processes under environments anddevices different in cleanliness. A problem has been presented even interms of the maintenance and control of cleanliness.

SUMMARY OF THE INVENTION

The present invention has been made in terms of the above problems andaims to achieve the following objects.

Namely, an object of the present invention is to provide a semiconductordevice in which the scope of selection of a resin is wide and adhesionbetween a substrate and the resin is excellent.

Another object of the present invention is to provide a method formanufacturing a semiconductor device, which is capable of preventingcracks of a semiconductor wafer at resin molding.

As a result of extensive investigations, the present inventors havefound that the above problems can be solved by using the followingsemiconductor device manufacturing method, thereby leading to theachievement of the above objects.

Namely, there is provided a semiconductor device according to thepresent invention, comprising a first area and a second area positionedadjacent to the outside of the first area, a semiconductor substratehaving a main surface and side surfaces and disposed in such a mannerthat the main surface is positioned in the first area and each of theside surfaces is positioned at a boundary between the first area and thesecond area, a plurality of pads formed over the main surface of thesemiconductor substrate and a plurality of external connecting terminalsformed thereon, which are respectively electrically connected to thepads, a first resin portion formed over the main surface of thesemiconductor substrate so as to cover the pads and having a mainsurface and side surfaces, the first resin portion being formed in sucha manner that the external connecting terminals are exposed from themain surface and each of the side surfaces is positioned at theboundary, and a second resin portion positioned in the second area andformed so as to cover the side surfaces of the semiconductor substrateand the side surfaces of the first resin portion, the second resinportion being different in composition from the first resin portion.

Further, there is provided a method for manufacturing a semiconductordevice formed by fractionization and division after a plurality ofsemiconductor element are formed over a semiconductor substrate,comprising the steps of forming a first resist portion over thesemiconductor substrate prior to its fractionization, forming trenchesin areas for dicing the semiconductor substrate, forming a second resinportion different in composition from the first resin portion in each ofthe trenches, and dicing the semiconductor substrate with respect to thesecond resin portion with widths each narrower than the trench therebyto bring the semiconductor device into fractionization and division.

According to the present invention, there can be provided asemiconductor device in which the scope of selection of a resin is wideand adhesion between a substrate and the resin is excellent.

According to the present invention as well, there can be provided amethod for manufacturing a semiconductor device, which is capable ofpreventing cracks of a semiconductor wafer at resin molding.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the subject matter which is regarded as theinvention, it is believed that the invention, the objects and featuresof the invention and further objects, features and advantages thereofwill be better understood from the following description taken inconnection with the accompanying drawings in which:

FIG. 1(A) is a top view of a semiconductor device according to anembodiment of the present invention and FIG. 1(B) is a sectional view ofthe semiconductor device shown in FIG. 1(A);

FIGS. 2A-2D are process sectional views of a method for manufacturing asemiconductor device according to an embodiment of the presentinvention;

FIGS. 3E-3G are process sectional views of the semiconductor devicemanufacturing method shown in FIG. 2;

FIGS. 4(A), 4(C), 4(E) and 4(G) are respective process top views forcharging a resin by a printing system of the method for manufacturingthe semiconductor device according to the embodiment of the presentinvention, and FIGS. 4(B), 4(D), 4(F) and 4(H) are respectively processsectional views for charging the resin by the printing system of themethod for manufacturing the semiconductor device according to theembodiment of the present invention; and

FIG. 5A-5E are process sectional views showing a conventionalsemiconductor device manufacturing method.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will hereinafter bedescribed with reference to the accompanying drawings. Incidentally, theshape, size and physical relationship of each constituent part orelement in the accompanying drawings are merely approximateillustrations to enable an understanding of the present invention. Thepresent invention is not limited by it in particular.

A semiconductor device of the present invention and a manufacturingmethod thereof will hereinafter be explained in detail.

<Semiconductor Device>

FIG. 1(A) is a transparent plan view for describing the physicalrelationship of each constituent element as viewed from above asemiconductor device 10. To make it easy to describe each formed wiringstructure, a sealing portion formed on the upper surface side thereof ispractically shown so as to be transparent. FIG. 1(B) is a typicalsectional view showing an area cut along a one-dot chain line indicatedby I-I of FIG. 1(A).

The semiconductor device 10 has a WCSP structure. Areas for configuringcircuit elements, i.e., required circuit elements are formed in asemiconductor substrate 12 by a wafer process. Incidentally, a substratearea formed with the circuit element configuring areas is designated at14 in FIGS. 1(A) and 1(B). In the following description, the substratearea is called simply “element area 14”. The element area 14 isgenerally configured by a plurality of active elements each having anintegrated circuit such as an LSI. In the following description, astructure including such an element area 14 formed on the semiconductorsubstrate 12 and comprising circuit element connecting pads 18 to bedescribed later, a passivation film 20 formed on the element area 14 soas to expose parts of the circuit element connecting pads 18, and aninsulating film 22 formed so as to expose parts of the circuit elementconnecting pads 18 is referred to as “semiconductor body 13”. In thesemiconductor body 13, the surface 14 a of the insulating film 22 isconfigured as the surface of the semiconductor body 13.

The semiconductor body 13 has a main surface and side surfaces. The mainsurface is located in a first area 40 in FIG. 1(B). Each of the sidesurfaces represents a side surface 42 located at a boundary between thefirst area 40 and a second area 50 in FIG. 1(B).

In FIG. 1(B), wiring structures 30 are provided on the semiconductorbody 13. Each of the wiring structures 30 may include an electrode post28 (also called “protruded electrode”) electrically connected to anexternal connecting terminal 32, and a redistribution wiring layer 24for electrically connecting the electrode post 28 and the circuitelement connecting pad 18. The wiring structure 30 may be a wiringstructure unprovided with the redistribution wiring layer 24 and theelectrode post 28, i.e., a structure in which the external connectingterminal 32 is placed on the circuit element connecting pad 18 throughthe insulating film 22 interposed therebetween. In this case, a firstresin section or portion 34 (sealing portion) to be described laterbecomes such a thin film that each external connecting terminal 32 isexposed onto the insulating film 22. Even among these, the wiringstructure preferably takes the structure including the redistributionwiring layer 24 and the electrode post 28. In this structure, some ofthe redistribution wiring layer 24 is configured as an electrode postpad 26, and the electrode post 28 is electrically connected to theelectrode post pad 26. Thus, each external connecting terminal 32 isexposed from the first resin portion 34 formed in the first area 40 andhence the position of the external connecting terminal 32 can besuitably selected according to the heights of the redistribution wiringlayer 24 and the electrode post 28. Therefore, the degree of freedom ofdesign of the semiconductor device might be enhanced.

In the semiconductor device 10 of the present invention, the first resinportion 34 is provided in the first area 40 so as to seal theredistribution wiring layer 24, the electrode post pads 26 and theelectrode posts 28. The first resin portion 34 is provided with a mainsurface and side surfaces. The external connecting terminals 32 areexposed from the main surface, and the side surface 44 is located at theboundary between the first area 40 and the second area 50 in a mannersimilar to the side surface 42 of the semiconductor body 13.

Further, a second resin section or portion 46 is located in the secondarea 50 and formed so as to cover the side surfaces 42 of thesemiconductor body 13 and the side surfaces 44 of the first resinportion 34.

In FIG. 1(A), a multilayer wiring structure (not shown and hereinaftercalled also “internal wiring”) is generally formed in the element area14 and the plural active elements are formed so as to be capable offulfilling their predetermined functions in cooperation with oneanother. The electrode pads 18, the passivation film (not shown in FIG.1(A)) and the insulating film (not shown in FIG. 1(A)) are provided overthe element area 14. According to the configuration shown in FIG. 1(A),the electrode pads 18 are provided along the outer peripheral-side arealying within the area of the semiconductor device 10 in such a mannerthat they become identical to one another in pitch defined therebetween.

The external connecting terminals 32 are disposed in the center sidearea of the semiconductor device 10, which is surrounded by the circuitelement connecting pads 18.

The external connecting terminals 32 are provided so as to be identicalin pitch defined therebetween. Further, the external connectingterminals 32 are electrically connected to their corresponding electrodepads 18 by the wiring structures 30 comprised of the redistributionwiring layer 24, the electrode post pads 26 and the electrode posts 28.

The semiconductor device 10 of the present invention is provided withthe second area 50 at the outer peripheral portion of the first area 40.As described above, the first resin portion (not shown in FIG. 1(A)) isformed in the first area 40, and the second resin portion (not shown inFIG. 1(A)) is formed in the second area 50.

The first resin portion 34 and the second resin portion 46 are differentin composition from each other. Particularly preferred is that thesecond resin portion 46 is excellent in adhesion to the semiconductorbody 13 and the first resin portion 34. This will be described later.

In the semiconductor device of the present invention having such aconfiguration, the first resin portion is required to have insulationprincipally, and the second resin portion is required to have adhesionto the first resin portion and the semiconductor substrate. Therefore, aresin or filler can be selected in such a manner that that the rightmaterial is put in the right place. The second resin portion is formedso as to cover the side surfaces of the first resin portion and the sidesurfaces of the semiconductor body. Thus, the area at which the secondresin portion and the semiconductor substrate contact each otherincreases, and the adhesion to the substrate by an anchor effect isexcellent. Further, such a configuration that the sides of thesemiconductor device are protected enables suppression of the directinfluence of the external environment thereon. In addition, when thesides of the semiconductor device are held by a handling device, thesemiconductor device can be prevented from being damaged by a handlingdevice when the sides of the semiconductor device are held by thehandling device.

In the present invention, the neighborhood of the portion where thefirst resin portion 34, the second resin portion 46 and thesemiconductor body 13 are joined to one another might be called “gripportion 60”.

As a preferred mode for the semiconductor device of the presentinvention, it is preferred that as shown in FIG. 1(B), the semiconductorsubstrate 12 has a first side surface and a second side surface 49, andthat the first side surface constitutes part of the side surface 42 ofthe semiconductor body 13 and the second side surface 49 is positionedat the outer end of the second area 50. In the case of such a structure,both of the first area 40 and the second area 50 are formed on thesemiconductor substrate 12. Further, in the case of such a structure,the thickness y of the second resin portion 46 is smaller than the sumof the thickness x of the first resin portion 34 and the thickness ofthe semiconductor body 13 and larger than the thickness x of the firstresin portion 34 in FIG. 1(B).

Since the area at which the second resin portion 46 and thesemiconductor substrate 12 contact each other increases, thesemiconductor device comprised of such a structure makes it possible toenhance the adhesion between the semiconductor substrate 12, the firstresist portion 34 and the second resin portion 46 by the anchor effectand suppress peeling off of the semiconductor substrate 12 from thefirst resin portion 34. Fractionization is enabled by one dicing in afinal process step subsequent to the formation of the externalconnecting terminals 32.

The first resin portion, the second resin portion and the grip portionwill hereinafter be explained in detail.

[First Resin Portion and Second Resin Portion]

Each of the first resin portion 34 and the second resin portion 46employed in the present invention includes a filler contained in aresin. With the containing of the filler therein, the flowability of theresin is adjusted and the flame resistance of the resin-portion is alsoenhanced. The second resin portion 46 is different in composition fromthe first resin portion. It is shown that when each of the first andsecond resin portions 34 and 46 is comprised of the resin and filter,any of forms different in resin and identical in filler, forms identicalin resin and different in filler, and forms different in resin andfiller is contained as the different compositions.

[Resin]

As the resin employed in the first resin portion 34, there may bementioned, for example, an epoxy resin, a polyimide resin,polybenzoxazole resin (PBO), a novolac resin, a phenol resin, an acrylicresin, an urethane resin, a silicone resin, PPS (Poly PhenyleneSulfide), polyethylene telephthalate (PET), polyethylene (PE), or amixed resin (WPR) or the like comprised principally of the novolac resinand the phenol resin. Since it is necessary to insulate betweenredistribution wirings, the resin needs to have insulation.

The semiconductor device of the present invention preferably has heatresistance of such an extent that it can withstand a reflow processbecause it passes through the reflow process upon formation of eachterminal. That is, the resin is preferably such a resin that a glasstransition temperature (Tg) becomes higher than a reflow temperature.Described specifically, as such a resin, there may be mentioned, evenamong the above-described resins, the epoxy resin, the polyimide resin,the polybenzoxazole resin (PBO), the mixed resin (WPR) comprisedprincipally of the novolac resin and the phenol resin, or the like.Incidentally, the mixing ratio (mass ratio) between the novolac resinand the phenol resin in WPR preferably ranges from 1:30 to 1:20.

The resin employed in the second resin portion 46 must take intoconsideration even the adhesion between the semiconductor body 13 andthe first resin portion 34 and the prevention of chipping or the like atthe dicing in addition to the adhesion, insulation and Tg or the like tothe semiconductor body 13. When the semiconductor device is divided intoindividuals, it is liable to be diced as its hardness becomes close tothe semiconductor substrate, and the occurrence of cracks or the likecan be suppressed. That is, as the resin used in the second resinportion 46, there may be mentioned the epoxy resin, polyimide resin,polybenzoxazole resin (PBO) or the mixed resin (WPR) comprisedprincipally of the novolac resin and the phenol resin. Incidentally, theresin is preferably the same resin as that employed in the first resinportion 34 if the adhesion to the first resin portion 34 is taken intoconsideration.

The second resin portion 46 employed in the present invention needs tobe provided with a trench or groove narrow in width, enhance a fillingproperty by a reduction in the viscosity of the resin and suppress theoccurrence of voids. Therefore, it is preferred that in order to adjustthe viscosity of the resin, a solvent such as ethyl lactate orN-methylpyrrolid or the like is suitable contained therein. It ispreferable that the content of the resin ranges from greater than orequal to 10 mass % to less than or equal to 60 mass % with respect tothe mass of the pre-curing resin.

[Filler]

A filler may preferably be contained in the first resin portion 34 andthe second resin portion 46 employed in the present invention. As thefiller employed in the present invention, it may preferably be aninsulative filler because there is a need to insulate betweenredistribution wirings. As the filler, there may be mentioned, forexample, alumina, silica, silicone rubber, BN or diamond or the like.Although the shape of each particle makes use of a normal sphere-shapedone, the particle may use a granular one, a shredded one, aphosphorus-flake shaped one, a dendritic one and the like. Even amongthese, a particle whose average circularity measured by a flow particleimage measuring device ranges from 0.975 or more to 1.000 or less, ispreferred. Since the particle shape is approximately spherical orspherical when the average circularity ranges within this range, theflowability of the filler is good and its filling property is alsoenhanced. It is thus possible to reduce the rate of occurrence of voidsin the second resin portion 46 and suppress chipping or the like at thedicing time. The corresponding circularity is of an index indicative ofthe degree of depressions and projections of the filler. When the filleris of a complete sphere, the circularity indicates 1.000. As the surfaceshape becomes more complex, the circularity becomes a small value.

The average circularity is measured using the flow particle imagemeasuring device ┌FPIA-2100 TYPE┘ (manufactured by Sysmex Corporation)and calculated using the following equation:Equivalent circle diameter=(particle projection area/π)^(1/2)×2Circularity=circumferential length of circle having the same area asparticle projection area/circumferential length of particle projectionimage   (1)

where the “particle projection area” indicates the area of a binarizedfiller particle image, and the “circumferential length of particleprojection image” is defined as the length of a profile or border lineobtained by connecting edge points of the filler particle image. Themeasurement is done using the circumferential length of a particle imageat image processing in an image processing resolution of 512×512 (pixelof 0.3 μm×0.3 μm).

Assuming that the circularity (center value) at a cutoff point i of aparticle size distribution is ci and the number of measured particles ism, average circularity C that means an average value of a circularityfrequency distribution is calculated from the following equation:

$\begin{matrix}{{{Average}\mspace{14mu}{circularity}\mspace{14mu} C} = {\sum\limits_{i = 1}^{m}\;{{ci}/m}}} & (2)\end{matrix}$

Incidentally, the measuring device ┌FPIA-2100┘ employed in the presentinvention calculates the circularities of respective particles andthereafter divides the particles into classes at which a circularity of0.4 to 1.0 is equally divided every 0.01, according to the obtainedcircularities upon calculation of the average circularity andcircularity standard deviation. Then, the measuring device calculatesthe average circularity and circularity standard deviation using thecenter value between their cutoff points and the number of the measuredparticles.

As a specific measuring method, an ion exchange water of 10 ml fromwhich impure solid materials or the like have been removed is preparedin a container in advance. A surface-active agent, preferablyalkylbenzene sulfonate is added into the container as a dispersingagent. Further, a sample to be measured of 0.02 g is added thereto,followed by execution of its uniform dispersion. Using an ultrasonicdispersing machine ┌Tetora 150 type┘(manufactured by Nikkaki-bios Co.,Ltd.) as dispersing means thereof, dispersion processing is done for twominutes to provide a dispersion solution for measurement. At this time,the dispersion solution is suitably cooled in such a manner that thetemperature of the dispersion solution does not reach 40° C. or higher.In order to suppress variations in the circularity, the installationenvironment of the flow particle image analyzing device FPIA-2100 iscontrolled to 23° C.±0.5° C. in such manner that the in-devicetemperature thereof becomes 26° C. to 27° C. An autofocusing adjustmentis done using 2-μm latex particles at 1-hour intervals, preferably 2hours intervals.

Upon the measurement of the filler's circularity, the flow particleimage measuring device is used to readjust the concentration of thedispersing solution in such a manner that a filler particleconcentration at its measurement ranges from 3000 to 10000 pieces/μl andthereby to measure filler particles of 1000 or more. After themeasurement thereof, the filler particles are respectively divided intoan equivalent circle diameter of greater than or equal to 0.6 μm to lessthan 3 μm, an equivalent circle diameter of greater than or equal to 3μm to less than 6 μm and an equivalent circle of greater than or equalto 6 μm to less than 400 μm using data about the measured fillerparticles. Then, the average circularity of the filler particles in theranges of the respective equivalent circle diameters is determined.

On the other hand, although there is a need to adjust the viscosity ofthe resin in order to provide the second resin portion 46, the viscositycan be adjusted by the average particle diameter of each of fillers orthe content thereof in addition to its adjustment by the type of resin,the solvent and the circularity of each filler.

Preferably, the fillers are contained in the second resin portion 46 andthe filler's average particle diameter in the present invention rangesfrom 0.2 μm or more to 40 μm or less. When the average particle diameterlies within this range, the viscosity of the resin for forming thesecond resin portion is reduced because the filler contained in thesecond resin portion is small, and the filling property of the resin isenhanced, whereby there is a case in which the resin can be chargedwithout producing voids even if the width of each groove is narrow.Here, the average particle diameter represents the average value of theequivalent circle diameters of the respective particles. The equivalentcircle diameters correspond to the equivalent circle diameters measuredby the flow particle image measuring device and are obtained by theabove equation.

In the present invention, the equivalent circle diameter preferablyranges from 0.2 μm or more to 40 μm or less. When it lies within thisrange, the flowability of the resin is satisfactory and the resin can becharged without producing voids even if each groove to be describedlater for forming the second resin portion is narrow. There is a casewhere when the equivalent circle diameter is under and not greater than0.2 μm, the fillers are flocculated together in the resin so that thesecond resin portion in which the fillers are dispersed uniformly cannotbe formed. There is also a case in which the fillers in the vicinity ofthe side surfaces of the semiconductor device are particle-shedded atdicing and hence the flatness of the surface thereof is damaged. On theother hand, there is a case in which when the equivalent circle diameteris larger than 40 m, the fillers cannot be penetrated into the groovesto be described later, and hence the filling property is deteriorated.

The content of the filler in the present invention preferably rangesfrom 40 mass % or more to 90 mass % or less with respect to the secondresin portion 46. This mass ratio indicates the ratio of the mass of theresin to the mass of the second resin portion 46 after a resin layer hasbeen formed and the resin has been cured. There is a case in which whenthe content is not greater than 40 mass %, the viscosity of thepre-print resin is excessively low so that the resin expands to terminalmounting spots of columnar electrodes. The problem of heat resistance orthe like also arises because the amount of filler is small. On the otherhand, there is a case in which when the content is greater than or equalto 90 mass %, the viscosity of the pre-print resin is excessively highso that its filling property is deteriorated.

As a preferred mode of the second resin portion 46 in the presentinvention, there is cited that the resin is an epoxy resin, a polyimideresin, a polybenzoxazole resin (PBO resin) or a mixed resin (WPR resin)comprised principally of a novolac resin and a phenol resin, the filleris alumina or silica, the equivalent circle diameter ranges from 0.2 μmor more to 40 μm or less, the average particle diameter of each offillers ranges from 0.2 μm or more to 40 μm or less, and the content offiller ranges from 40 mass % or more to 90 mass % or less. Incidentally,the type of resin can be suitably selected in consideration of theadhesion between the first resin portion 34 and the semiconductorsubstrate 12.

The first resin portion 34 indicates a form similar to the normal moldresin and makes use of an epoxy resin, for example. The average particlediameter of the filler ranges from 50 μm or more to 60 μm or less. Thecontent of filler ranges from about 70 mass % or more to 80 mass % orless with respect to the first resin portion. This mass ratiocorresponds to the ratio of the mass thereof to the total mass of thefirst resin portion after the resin has been cured.

Thus, the average particle diameter of the filler contained in thesecond resin portion 46 is preferably smaller than the average particlediameter of the filler contained in the first resin portion 34. Thecontent of each filler contained in the second resin portion 46 ispreferably lower than the content of each filler contained in the firstresin portion 34. Namely, it is shown that when the content of the firstfiler is 80 mass % with respect to the total mass of the first resinportion 34, the content of the second filler is less than 80 mass % withrespect to the total mass of the second resin portion 46. With thesetting of this range, the anchor effect of the second resin portion 46can be more achieved.

As shown in FIG. 1(B), the thickness x of the first resin portion 34corresponds to the height from the surface of the semiconductor body 13,i.e., the surface of the insulating film 22 to the surface of eachelectrode post 28 and ranges from about 30 μm to 120 μm, for example.

The thickness y of the second resin portion 46 corresponds to the heightfrom the bottom face of the grip portion to be described later to thesurface of each electrode post 28. The width z thereof corresponds tothe width of the grip 60. The details thereof will be explained later.

[Grip Portion]

The semiconductor device according to the present invention preferablyhas the grip portion 60 at the side portion as viewed in the sectionalshape of the semiconductor substrate as shown in FIG. 1.

The grip portion 60 corresponds to a spot at which the second resinportion 46 is provided. Since the area at which the second resin portion46 and the semiconductor body 13 contact increases as compared with thecase free of the provision of the grip portion 60, the peeling off ofthese can be suppressed. Even if voids have occurred between the bottomof the first resin portion 34 and the semiconductor body 13 in FIG.1(B), moisture or the like does not reach the redistribution wiringlayer 24 because the sidewall 44 of the first resin portion 34 and thesidewall 42 of the semiconductor body 13 are adhered to the second resinportion 46 by an anchor effect.

The height of the grip portion 60 in the present invention, i.e., thethickness y of the second resin portion 46 preferably ranges from 50 μmor more to 200 μm or less. Since the anchor effect is more enhanced whenit lies within this range, the second resin portion 46 and thesemiconductor substrate 12, and the second resin portion 46 and thesemiconductor body 13 become hard to peel off. Further, environmentalresistance is also excellent because they are hard to peel off.

The width z of the grip portion in the present invention preferablyranges from 5 μm or more to 30 μm or less. With the grip portion beingprovided with the width of 5 μm or more, the moisture or the like doesnot reach the redistribution wiring portion because it has a sufficientwidth even if the moisture or the like enters the surface of the secondresin portion. When the width is 30 μm or less, the size of thesemiconductor device itself is not excessively large and adaptation to ademand for its size reduction can be achieved.

<Manufacturing Method of Semiconductor Device>

The semiconductor device manufacturing method of the present inventionis a method for manufacturing a semiconductor device formed byfractionizing and division after a plurality of semiconductor elementsare formed on a semiconductor substrate, which comprises the steps offorming a first resin portion on the semiconductor substrate prior tofractionization thereof, forming grooves or trenches in regions fordicing the semiconductor substrate, forming a second resin portion ineach of the trenches, and dicing the semiconductor substrate withrespect to the second resin portion with widths each narrower than thetrench thereby to bring the semiconductor device into fractionizationand division.

Since the trenches are formed after the formation of the molded firstresin portion where these process steps are provided, it is possible tosuppress a reduction in the strength of the substrate even after thetrench formation and suppress cracks of the semiconductor substrate withthe trenches as points of origin. Since the redistribution wirings andcolumnar substrate have already been covered with the first resinportion upon trench formation, chips or particles generated or producedupon the formation of the trenches are not adhered thereto. There is noneed to perform a cleaning process for eliminating the chips andparticles. It is also unnecessary to consider a cleaning device,cleaning environment and the like.

With a manufacturing method of a semiconductor device 100 of the presentinvention as one example, respective process steps thereof willhereinafter be described in detail along FIGS. 2 and 3.

[Step for Forming First Resin Portion on the Semiconductor SubstratePrior to its Fractionization]

In the present invention, a semiconductor body 13 is formed as shown inFIG. 2(A). An element area 14 and circuit element connecting pads 18 arefirst sequentially formed on a semiconductor substrate 12. A passivationfilm 20 is formed on the element area 14 in such a manner that thecircuit element connecting pads 18 are exposed. Then, an insulating film22 is formed on the passivation film 20 in such a manner that thecircuit element connecting pads 18 are exposed.

Next, wiring structures 30 are formed. A redistribution wiring layer 24is first drawn or led out from each of the circuit element connectingpads 18. Then, electrode posts 28 electrically connected to externalconnecting terminals are provided according to a plating step.Incidentally, some of the redistribution wiring layer 24 are formed aselectrode post pads 26. The electrode posts 28 are electricallyconnected to their corresponding electrode post pads 26.

Thereafter, as shown in FIG. 2(B), a first resin portion 34 is formed onthe semiconductor substrate 12 by the known technique such as the spincoat method so as to cover the redistribution wiring layer 24 and theelectrode posts 28. The first resin portion 34 has such a thickness t1that the electrode posts 28 are covered, and is provided such that t1becomes 120 μm or so, for example. The first resin portion 34 has theresin described above and fillers contained in the resin.

[Step for Forming Trenches or Grooves in Dicing Areas of SemiconductorSubstrate]

As shown in FIG. 2(C), trenches 70 are provided in such a manner that apredetermined depth t2 is formed in the surface of the semiconductorsubstrate 12 by a blade (not shown) that rotates at high speed. Sincethe first resin portion 34 has been formed in the present invention,adverse effects exerted on the redistribution wiring layer 24 and theelectrode posts 28 by re-adhesion of chips or the like to thesemiconductor element area can be reduced even though dicing is done inthe corresponding process step.

The trenches 70 are formed at their corresponding portions each formedas a peripheral portion of each semiconductor element. The depth (t1+t2)of each of the trenches 70 preferably ranges from 50 μm or more to 200μm or less. If the depth is 50 μm or more, then stress applied to thesemiconductor substrate upon dicing at the fractionization of thesemiconductor device can be reduced. It is possible to form a stablewidth without depending on the shape of the blade. On the other hand, ifthe depth is 20 μm or less, then the semiconductor substrate located atthe bottom face of each trench 70 is not excessively thin. Assuming thatthe depth of the trench 70 is 180 μm or so, for example, t1 shown inFIG. 2(B) becomes 120 μm and t2 shown in FIG. 2(C) becomes 60 μm.

The width w of the trench 70 preferably ranges from 40 μm or more to 180μm or less. The width w thereof needs to be at least larger than thethickness of the blade used upon fractionization and division to bedescribed later. If the width of the trench 70 is narrower that theblade thickness, then no grip portion 60 is formed, and thesemiconductor substrate 12 and the first resin portion 34 are directlydiced. Namely, when the semiconductor substrate of such a configurationas not to have the conventional grip portion is diced, it leads tocracks produced in the semiconductor substrate and the first resinportion. Assuming that the blade thickness used upon formation of eachtrench 70 in the semiconductor substrate ranges from 5 μm or more to 150μm or less upon formation of the width of each trench 70, the width isformed larger by 1 to 5 μm than its range. Thus, a blade having athickness made thin by about 1 to 5 μm is preferably used to obtain adesired width.

[Step for Forming Each Second Resin Portion in the Trench]

A second resin portion 46 is formed so as to bury each trench 70 asshown in FIG. 2(D).

A method for forming each second resin portion 46 is preferably aprinting method or system and a dispense method or system.

The printing method is as follow: As shown in FIG. 4(A), for example, asemiconductor substrate 12 formed with trenches 70 is disposed below amask 90. As shown in FIG. 4(C), a resin 50 a containing the abovefillers is placed on the mask 90. Next, as shown in FIG. 4(E), a resinis extended with a printing brush (not shown) and a second resin portion46 extruded out of the mask 90 is formed so as to bury each trench 70 ofthe semiconductor substrate 12. At this time, the printing brush (notshown) is preferably moved forward and backward alternately two or threetimes such that the resin 50 a is changed into each trench 70 uniformly.Further, it is particularly preferred that when the printing brush (notshown) is moved from side to side alone, the resin is uniformly chargedby the printing brush (not shown) after the semiconductor substrate 12or the mask 90 is rotated 90°, to uniformly charge the resin even intoeach trench lying in the direction orthogonal to the movement of theprinting brush (not shown). It is also particularly preferred that theprinting brush is moved in the vertical direction. Such a method makesit possible to form the second resin portion 46 on the semiconductorsubstrate 12 easily.

Thus, in the present invention, while the mask 90 is pressurized uponextrusion of the resin, the semiconductor substrate 12 is alsopressurized because the distance between the mask 90 and thesemiconductor substrate 12 is very narrow. Since, however, the presentmethod is different from the conventional manufacturing method in thepresent invention and the first resin portion 34 has been formed uponcharging of the resin 50 a, the strength of the semiconductor substrate12 is reinforced by the formation of the trenches 70. Thus, even thoughthe pressure is applied more or less, cracks of the semiconductorsubstrate 12 with the trenches 70 as points of origin can be prevented.

The dispense method is of a method for injecting a resin into a slenderpen-shaped dispenser and injecting the resin at the inside of eachtrench 70 from the leading end or tip of the dispenser. Since thesemiconductor substrate 12 is not pressurized upon resin injection inthe present method, the cracks with the trenches 70 as the points oforigin are further suppressed. Namely, since each of the trenches 70 canbe made deeper when the resin is charged by the dispenser method, thesecond resin portion 26 is thickened. As a result, the pressure andshock applied to the semiconductor substrate 12 when semiconductorelements are brought into fractionization and division by dicing can bereduced. Further, since the anchor effect by each second resin portionis more enhanced as described above, the second resin portion 46 and thesemiconductor substrate 12 become hard to peel off.

After the formation of each second resin portion 46 as described above,parts of the second resin portion 46 and extra spots of the first resinportion 34 are ground as shown in FIG. 3(E) to expose the surfaces ofthe electrode posts 28. After the grinding, the second resin portion 46formed at the grip portion 60 is left behind. Thereafter, as shown inFIG. 3(F), external connecting terminals 32 are placed on theircorresponding exposed surface of electrode posts 28, and the externalconnecting terminals 32 are electrically connected to the electrodeposts 28 by a reflow process step.

[Step for Dicing the Substrate at Each Central Part of the Second ResinPortion with Widths Each Being Narrower than the Trench thereby to Bringthe Semiconductor Device into Fractionization and Division.

Finally, as shown in FIG. 3(G), the semiconductor devices can beobtained by conducting fractionizing and division from the respectivecenter of the second resin portion 46 with a blade having a thicknessnarrower than the width of each trench 70. At this time, such one thatthe width z of the second resin portion 46 falls within the above rangeis selected as the blade thickness. The position where dicing is done inthe corresponding process step, is preferably set to the central part ofeach second resin portion 46. The “central part” indicates such aposition that each second resin portion 46 has at least the width zlying within the above range in each post-division semiconductor device.Even among such positions, such positions that the widths z of allsemiconductor devices become identical are preferably diced inconsideration of dimensional accuracy of each individual semiconductordevice.

While the preferred forms of the present invention have been described,it is to be understood that modifications will be apparent to thoseskilled in the art without departing from the spirit of the invention.The scope of the invention is to be determined solely by the followingclaims.

1. A semiconductor device, comprising: a first area, and a second areapositioned adjacent to an outside of the first area; a semiconductorsubstrate having a main surface and side surfaces and disposed in such amanner that the main surface is positioned in the first area and each ofthe side surfaces is positioned at a boundary between the first area andthe second area; a plurality of pads formed over the main surface of thesemiconductor substrate; an insulating film formed over the main surfaceof the semiconductor substrate with the pads being exposed therefrom; aplurality of external connecting terminals formed over the insulatingfilm, which are respectively electrically connected to the pads; a firstsealing resin portion formed over the main surface of the semiconductorsubstrate so as to cover the pads and the insulating film having a mainsurface and outermost side surfaces, said first sealing resin portionbeing formed in such a manner that the external connecting terminals areexposed from the main surface of the first sealing resin portion andeach of the outermost side surfaces of the first sealing resin portionis positioned at the boundary; and a second sealing resin portionpositioned in the second area and formed so as to cover the sidesurfaces of the semiconductor substrate and to completely cover theoutermost side surfaces of the first sealing resin portion and theinsulating film, said second sealing resin portion being different incomposition from the first sealing resin portion.
 2. The semiconductordevice according to claim 1, wherein the semiconductor substrate has afirst side surface and a second side surface located at the outside fromthe first side surface, wherein the first side surface corresponds tothe side surface of the semiconductor substrate, and wherein the secondside surface is positioned to an end at the outside, of the second area.3. The semiconductor device according to claim 1, wherein the thicknessof the second sealing resin portion is smaller than the sum of thethickness of the semiconductor substrate and the thickness of the firstsealing resin portion and larger than the thickness of the first sealingresin portion.
 4. The semiconductor device according to claim 1, whereinthe external connecting terminals are respectively exposed from the mainsurface via redistribution wirings and columnar electrodes as viewedfrom the corresponding terminals lying over the semiconductor substrate.5. The semiconductor device according to claim 1, wherein a first filleris contained in the first sealing resin portion, where a second filleris contained in the second sealing resin portion, and wherein thecontent of the second filler relative to the second sealing resinportion is lower than the content of the first filler relative to thefirst sealing resin portion.
 6. The semiconductor device according toclaims 1, wherein a first filler is contained in the first sealing resinportion, where a second filler is contained in the second sealing resinportion, and wherein the average particle diameter of the second filleris smaller than the average particle diameter of the first filler.